LAAM (levo-alpha acetylmethadol) is a long-acting opioid mu agonist similar to methadone but with a slower onset and longer duration of action. It's pharmacokinetic profile offers the distinct clinical advantage of a three time per week dosing schedule for use in the treatment of opioid drug abuse. However, there is currently insufficient information concerning many of the parameters of clinical treatment including optimal stable dosing levels as well as a lack of information about the relative performance of LAAM treatment in relation to other available pharmacotherapies for opioid abuse. Two studies are proposed: 1) a dose response study of LAAM in a contemporary opioid dependent population and 2) a medication comparison study contrasting treatment outcome for four pharmacotherapies including LAAM. With the introduction of LAAM into the treatment community, it is reasonable to expect that facilities will adopt a high or low dose philosophy similar to that seen with methadone. The first clinical study proposed in this component is designed to provide information regarding the appropriate dosing of LAAM when used in the recommended three time per week dosing schedule. With the development of new agonist treatment medications for opioid drug abuse including LAAM and buprenorphine, there are important clinical decisions that will have to be made in the future concerning selection of the most appropriate medication from among the newly available treatment medications. The second proposed clinical study will assess the comparative efficacy of three times per week LAAM in relation to both standard (methadone at two different dose levels) and novel (3X per week buprenorphine) treatment regimens. A range of outcome measures will he assessed in both studies including primary measures of: 1) retention time in treatment, 2) opioid drug use, 3) psychosocial adjustment, and 4) staff global assessment while secondary measures will include: 1) use of non- opioid drugs 2) side effects data, 3) safety data, and 4) characteristics of patients with good versus poor outcomes. Both studies will utilize rigorous clinical trials methodology to provide critical scientific data for developing policy decisions regarding the optimal dosing of LAAM and for making rational choices among the agonist medications newly available for opioid drug abuse treatment.